Summary

This is a non blinded prospective randomized clinical trial to define the efficacy of a new
technology developed at the Cleveland Clinic to improve the positioning of the glenoid
component in total shoulder arthroplasty. The Cleveland Clinic research team has worked on
the development and validation of this new technology for the last six years. The
investigators have validated the pre-operative planning software and published the results
in the peer review literature (1, 7, 8, 9). The investigators have used this software in the
planning of total shoulder surgery over the last three years. The investigators have
validated the accuracy and reproducibility of the patient-specific instrumentation in both
cadaver shoulders and Sawbones models of the shoulder using multiple surgeons. These studies
also validated our ability to precisely measure component position using 3D CT scan imaging
after placement of the implants in a pre-clinical cadaver study, thereby validating our
ability to accurately measure and compare component position between the groups described in
this proposed clinical trial. The investigators have also proven the ability of the software
and techniques to produce an accurate representation of the glenoid morphology in patients
with osteoarthritis or rotator cuff deficient arthritis in 13 patients. This was an IRB
approved patient safety study performed at the Cleveland Clinic. The investigators have
performed extensive studies of the materials and processes for the fabrication,
sterilization and packaging of the patient specific instruments. The investigators have
selected materials and processes that have met all of the FDA requirements for use of these
materials and processes as clinical devices in vivo. These devices (non implanted
instruments) are generally classified by FDA as a Class I device not having significant
clinical risk. The investigators have studied the materials and process to produce accurate
instruments that meet the clinical specification for fit onto the surrogate glenoid surfaces
and maintain this shape and fit after sterilization. These same patient specific instruments
have been tested in pre-clinical trials (Sawbones and Cadavers), demonstrating their ability
to perform the functions specified with a high level of accuracy and much better than the
use of standard generic instruments.

Study Design

For the patients randomized to the GPS group, the surgeon will be given the GPS patient specific instrumentation and a model of the glenoid surface showing the exact placement and fit of the GPS alignment instruments.

glenoid positioning system

Design and fabrication of patient specific instrument for placement of a guide pin to be used to aid in bone preparation for placement of a metaglene and its fixation screws or anatomic glenoid component

Each surgeon will use their standard methods of pre-operative planning using the pre-operative x-rays and CT scan.

Primary Outcomes

Measure

Comparing Glenoid component positioning to pre operative planning

time frame:
1 month post op

Secondary Outcomes

Measure

Intra-operative photographs

time frame:
Post Op CT within 1 year from surgery

Eligibility Criteria

Male or female participants of any age.

Inclusion Criteria:
- All patients otherwise indicated for primary reverse or anatomic total shoulder
replacement that are able to get a pre-operative CT scan at the Cleveland Clinic will
be considered eligible for enrollment. All patients will be consented in the office
as part of the pre-operative consent for surgery and all will need to randomization
at the time of surgery
Exclusion Criteria:
- Patients will be excluded if they have significant metal in the joint that results in
metal artifact on the CT scan, thereby compromising the ability to visualize the
glenoid on the pre-operative simulator.